Printing of paper or textile strips



Sept. 15, 1936.4 I G. WULF 2,054,763

PRINTING OF PAPER OR TEXTILE STRIPS Filed Jan. 8, 1934 m, m, j ME Patented Sept. 15, 1936 "UN I TED STATES i AT'EN T O F Fl CE Application January 8, 1934, Serial No; 705,800 In Germany July .27, 1933 4 Claims.

Present-day tasteshows a preference for paper and textile strips, which have .the same ground colour on their whole surface, this colour being shaded. Obtaining such shaded coloured surfaces has up to .now presented difliculties. It has been attempted, as 'a :help, to compose the strip of individual separately prepared portions or to effect various colouring operations in succession. Smooth shading of colour could nothowever, readily be obtained in this manner, and it was not possible in any-manner to obtain shaded colour-surfaces by means of a machine in a single operation.

The invention-solves the problem of obtaining in a single operation paper and textile strips having coloured surfaces shaded as desired, the shading for instance developing in one sense either gradually or .in distinct steps over the whole length of the strip. The solution of this problem is effected according to the :invention by arranging for the pressure between :two of the rollers conveying colour to the strip to vary periodically, thus causing the amount of colour supplied to the printing roller tojbe varied.

Printing arrangements are already :known in which by reason of irregularities in the. surface of an additional pattern roller acting-on the printing roller the colouring matter is removed to a greater or less extent fromthe printing roller, a pattern thus being obtained. But apart from the fact that the necessity .for preventing the roller from becoming saturated with 'colour requires special cleaning devices and results in waste of colouring matter there is neither intended nor obtainable according .to this process variation in the shade of the colour-over the whole length of the strip.

There is also known an arrangement in which the colour which is spread on to the strip in a wet state and serves for the background is distributed by squeezing rollers having raised and indented portions. In this case use is also made of the knowledge that variations in density of the colour can be obtained by corresponding adjustment of the pressure between the printing roller and the paper strip.

The invention relates on the contrary to those printing arrangements in which rollers charged with a single colour act on the surfaces to be printed, in which therefore the rollers effect in the same operation colouring and patterning.

According to the invention the pressure be tween colour conveying elements is varied periodically in a predetermined manner during the printing of one and the same paper or other strip instead of being initially adjusted and remaining constant during the printing. There are obtained in this manner different colour densities and unusual and rapidly alternating shades of colour can be obtained, in which the stages are well defined or again can be so small that they are not visible to the naked eye. In addition the invention can be carried out with very simple apparatus; it requires no additional pattern rollers, :no cleaning devices and avoids waste of colouring-matter.

The necessity for the matching of wall paper strips requires regular variations in pressure. These are effected automatically in that the pressuresare controlled positively with the movement of the strip of paper or other material.

.A particular and quickly repeating pattern is obtained according to one constructional form of the invention by means of adevicaiinwhich parts of the surface of a roller :are so displaced with respect'to one anotherthat the pressures exerted by these parts of the roller are phase-displaced.

Thevariationsin the pressures can be obtained in a simple manner by forming the roller or parts thereofeccentrically.

The invention is illustrated by way of example inthe accompanying drawing,

Fig. l is a side view of the apparatus,

Fig. 2 is a plan view of the apparatus illustrated in Fig. 1,

Fig. 3 illustrates on an. enlarged'scale a shaped cam,

Fig. 4 is a plan view of the cam illustrated in Fig. 3.

Theapparatuscomprises a frame ato which are secured. bearings b for the. shaft 0 which is operatedzby meansof the pulley'wheel d. On the shaft aiszsecured a drum 6. The paper or textile strip passes over the drum c. On the shaft 0 is mount ed a sprocket wheel g, which drives the sprocket wheel i by means of the chain h. The sprocket wheel 2' is mounted on the shaft is which is mounted in bearings l on the frame a. Cam discs m are secured on the shaft is. The cam discs m contact with rollers n which are carried by axially movable bolts 0. Secured to the bolts 0 are bearings p for the axle of an intermediate roller q. Each bolt 0 is carried by brackets r. Springs s tend to keep the rollers n in constant contact with the cam discs m.

The intermediate roller q obtains the colour from the taking-up roller t which takes the colour from the trough u. The intermediate roller q transfers the colour to the printing roller '11, which is mounted in bearings w on the frame a. From the printing roller the colour passes on to the paper or textile strip 1'.

Upon rotation of the cam discs m, the pressure of the roller q against the roller 1) is periodically varied in accordance with the movement of the paper or textile strip f, which passes over the drum e. The speed of the shaft is can be arranged to be varied by the substitution of exchangeable sprocket wheels having a different gear ratio for the sprocket wheels g and i.

In operation the cam discs m rotate with the other rollers. This causes the bearings p of the intermediate rollers q to move periodically. This movement may range from fractions of a millimetre to several millimetres according to the particular form of the cam disc. By the movement of the bearings 10, the pressure of the intermediate roller q against the printing roller 22 is varied. With an increased pressure the amount of colour passing from q to v is decreased, whereas the amount of colour passing increases when the pressure decreases. In this manner the supply of colour to the paper or textile strip is correspondingly graduated. The speed of rotation of the cam discs m can be so selected that the pressure is lowest at the commencement of the printing of the strip, and gradually rises to its maximum value as the end of the strip is reached. In this case a shading is obtained in which there is a gradual change from the deepest to the lightest shade of colour without distinct stages. If the cam discs m are permitted to rotate more rapidly, then a periodic variation of shade can be obtained. According to the shape of the cam discs the increases or decreases can be arranged to be more or less gradual. The cam discs for the two bearings may also be so formed that the one cam disc produces the maximum pressure when the other cam disc produces the minimum pressure, and vice versa.

If the cam disc m is given a conformation such as is illustrated diagrammatically in Figures 3 and 4, then there are obtained stepped alterations in the pressure of the intermediate roller q on the printing roller 12, and a shading is obtained having distinct stages.

In many cases cam discs m or the equivalent are entirely unnecessary, i. e. when the intermediate roller q is not cylindrical, but is formed eccentrically 0r similarly, the supports not then being movable. The form of the intermediate roller itself then causes a periodic variation in the pressure between q and v.

The invention may be used in conjunction with smooth or patterned printing rollers. The variations in pressure need not take place between the printing roller and the intermediate roller in contact with it, but can also take place at the point of contact of two intermediate rollers or one intermediate roller and the taking-up roller. The further the point of pressure variation lies from the printing roller, the less distinct are the colour shadings obtained, so that much more gradual changes from one shade to another are therefore obtained.

Having now described my invention, what I claim as new and desire to secure by Letters Patent is:

1. In a machine for printing a paper or textile strip with a single colour, a series of rollers in continuous succcessive engagement for conveying colour to said strip, bearings'for an intermediate roller in said series and means operating in accordance with the movement of the strip to impart a toeand-fro movement to said bearings.

2. In a machine for printing a paper or textile strip with a single colour, a series of rollers in continuous succcessive engagement for conveying colour to said strip, a rotatable drum, a printing roller in said series to contact with a strip passing over said drum, an intermediate roller in said series for imparting colour to said printing roller, bearings for said intermediate roller, springs urging said bearings away from said printing roller, and cams operatively connected to said drum and opposing said springs to a varying extent during rotation of said drum.

3. In a machine for printing a paper or textile strip with a single colour, a series of rollers in continuous successive engagement for conveying colour to said strip, a frame, a drum rotatably mounted on said frame, a printing roller in said series rotatably mounted on said frame to contact with a strip passing over said drum, a cylindrical roller in said series for imparting colour to said printing roller, bearings for said cylindrical roller mounted on said frame and movable towards or away from said printing roller, springs urging said bearings away from said printing roller, cams mounted on said frame and operatively connected with said drum to oppose the springs to a varying extent during rotation of said drum, 9. colour trough, and a roller mounted on said frame to contact with said intermediate roller and supply colour thereto from said trough.

4. In a machine for printing a paper or textile strip with a'single color, the combination of a series of rollers in continuous successive engagement for conveying color to said strip, the roller.

at the end of said series being in continuous engagement with said strip and means for varying the pressure of engagement between another roller of said series and its adjacent roller so as to vary the color transmitted to said latter roller.

GERHARD WULF. 

